* {
  margin: 0;
  padding: 0;
  border: none;
}
ul,
ol {
  list-style: none;
}
a {
  text-decoration: none;
}
body {
  background: #f0f0f0;
  color: red;
}
.width-height {
  width: 200px;
  height: 200px;
}
.div1 {
  width: 200px;
  height: 200px;
  border: 1px solid #000;
  background: #fff;
}
.div2 {
  width: 200px;
  height: 200px;
  background: red;
  color: #fff;
  border: 3px solid orange;
}
.div3 {
  border-top: 5px solid #000;
  border-left: 5px dashed transparent;
  border-right: 5px dashed transparent;
  width: 0;
  height: 0;
  overflow: hidden;
  position: relative;
}
.div4 {
  border-bottom: 10px solid red;
  border-left: 10px dashed transparent;
  border-right: 10px dashed transparent;
  width: 0;
  height: 0;
  overflow: hidden;
}
.div5 {
  border-left: 20px solid orange;
  border-top: 20px dashed transparent;
  border-bottom: 20px solid transparent;
  width: 0;
  height: 0;
  overflow: hidden;
}
.div3 {
  position: relative;
}
.list {
  width: 400px;
  overflow: hidden;
}
.list li {
  height: 30px;
  line-height: 30px;
  overflow: hidden;
  background: pink;
  margin-bottom: 5px;
  padding: 0 5px;
}
.list a {
  color: #444;
  float: left;
}
.list a:hover {
  color: red;
}
.list span {
  float: right;
}
.list {
  border: 1px solid red;
}
a {
  background-size: 100%;
}
